<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        .card_box{
            width: 400px;
            height: 200px;
            position: absolute;
            top:50%;
            left: 50%;
            margin-top: -100px;
            margin-left: -200px;
        }
        .card_box:hover{
            transform: rotateZ(180deg);
        }
        .front,.back{
            position: absolute;
            width: 100%;
            height: 100%;
            background: #ccc;
            z-index: 10;
        }
        .back{
            background: rgb(187, 107, 107);
            transform: rotateZ(180deg);
            z-index: 5;
        }
    </style>
</head>
<body>
    <div class="card_box">
        <div class="front">hello</div>
        <div class="back">world</div>
    </div>
</body>
</html>